Abstract
Quantum interfaces (QIs) that generate entanglement between photonic and spin-wave (atomic memory) qubits are basic building block for quantum repeaters. Realizing ensemble-based repeaters in practice requires quantum memory providing long lifetimes and multimode capacity. Significant progress has been achieved on these separate goals. The remaining challenge is to combine the two attributes into a single QI. Here, by establishing spatial multimode, magnetic-field-insensitive and long-wavelength spin-wave storage in laser-cooled atoms inside a phase-passively-stabilized polarization interferometer, we constructed a multiplexed QI that stores up to three long-lived spin-wave qubits. Using a feed-forward-controlled system, we demonstrated that a multiplexed QI gives rise to a 3-fold increase in the atom–photon (photon–photon) entanglement-generation probability compared with single-mode QIs. For our multiplexed QI, the measured Bell parameter is 2.51±0.01 combined with a memory lifetime of up to 1 ms. This work represents a key step forward in realizing fiber-based long-distance quantum communications.
Highlights
Quantum interfaces (QIs) that generate entanglement between photonic and spin-wave qubits are basic building block for quantum repeaters
Long-lived (0.1 s) and non-multiplexed atom–photon entanglement was demonstrated in optical-lattice atoms[38], in which the memory qubit was stored as two spatiallydistinct spin wave (SW), both associated with the 0 $ 0 magnetic-fieldinsensitive coherence, and the corresponding photonic qubit encoded into two arms of a Mach–Zehnder interferometer
The cold atomic ensemble was centered in a polarization interferometer formed by BD1 and BD2
Summary
Quantum interfaces (QIs) that generate entanglement between photonic and spin-wave (atomic memory) qubits are basic building block for quantum repeaters. The atomic-ensemble-based nodes, which were initially proposed in the Duan–Lukin–Cirac–Zoller (DLCZ) protocol[4], are formed by quantum interface (QIs) that create quantum correlations between a spin wave (SW) and a photon via spontaneous Raman emissions (SREs) induced by a write pulse[2,16,17,18,19,20,21,22,23,24,25,26,27,28,29]. Long-lived (0.1 s) and non-multiplexed atom–photon entanglement was demonstrated in optical-lattice atoms[38], in which the memory qubit was stored as two spatiallydistinct SWs, both associated with the 0 $ 0 magnetic-fieldinsensitive coherence, and the corresponding photonic qubit encoded into two arms of a Mach–Zehnder interferometer. With temporal multimode DLCZ-like QMs employing REID crystal[60], Kutluer and colleagues[33] experimentally demonstrated singlemode time-bin entanglement between a SW and a photon
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
